Method of and apparatus for treating metals



May 29, 1923.: 7 R. F. TRIMBLE METHOD OF AND APPARATUS FOR TREATING METALS Filed July 19, 1919 Patented May 29, 1923.

UNITED STATES PATENT OFFICE.

RUSSELL F. TRIMBLE, F ELIZABETH, NEW JERSEY; ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORA'IWSD, OF NEW YORK, N. Y. A CORPORATION OF NEW- YORK.

METHOD OF AND APPARATUS FOR TREATING METALS.

Application filed July 19, 1919. Serial No. 311,942.

To all whom it may concern.

Be it known that I, RUssELL F.'TRIMBLE,

a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus" for Treating Metals, of which the following is a full, clear, concise,

and exact description.

This invention relates to amethod and apparatus for treating metal and has particular reference to the treatment of metal which is to be used in an evacuated vessel such as a vacuum tube.

An object of the invention is to subject a large blank of the metal to a preliminary treatmentwhereby a large amount of the occluded gases andother matter is drivenv therefrom so that considerable time is saved when the metal later, as an electrode in a vacuum tube, is subjected to a similar treatment. I Y

Another object of the invention 1s to pro-. vide an apparatus whereby the metal may be so treated in considerable quantity and thereb result in an economy of time in the operation.

The invention in general comprises the 1nsertion of a considerable quantity of the metal to be treated into a vessel which is connected to an evacuation pump system, and while the gases are being pumped from said vessel, sub ecting said metal to an electrio current which heats it, preferably to incandescence, whereby the occluded gases and other matter resident in the metal tend to be driven ofi. y

The invention is illustrated in the drawing of which Fig. 1 is a central longitudinalsection partly in elevation of the device; Fig. 2 is a diagrammatic view of the system as a whole; and Fig. 3 shows a vacuum tube 1n which the metal treated in accordance with this invention is used as an electrode. as As shown in Fig. 1, the apparatus comprises a cylindricalvessel 1 having a cylindrical water jacket 2. These two vessels are sealed at their upper ends by an annular ring of parking 3 upon which a circular plate 4 of glass or other suitable air-tight material is adapted to rest. Between the plate 4 and the packing ring 3 there may be placed some viscous material, such as a heavy'oil to further insure the sealing of the inner chamber from the air. Suitable pipe connections 5 and 6 to the water jacket 2 permit a circulation of cooling fluid therethrough. In the bottom of the chamber 1 is positioned a pipe connection 7 which extends thence through the water jacket to the outside of the apparatusand is adapted to be connected to a suitable vacuum pump line. A pair ofterminals 8 and 9 having suitable adjustable connections 10 and. 11 are adapted to be connected to a quantity of metal 12 which is shown in the form of a strip. These terminals 8 and 9 are connected by rods 13 and 14 to electrical circuit wires 15 and 16, by means of binding posts 17 and 18. The rods 13 and 14 are passed through suitable apertures in the plate 4, and means comprising threaded sleeves 19 and 20 and suitable locking nuts 21 to 24 are used to make the connection air-tight.

The strip 12, as shown in Fig. 1, may be of nickel since this is one of the metals which is used particularl for plate electrodes of vacuum tubes. It is subjected to the treatment in the form of long strips although it is later divided into a plurality of smal er surfaces of the proper size.

In Fig. 2 which is a diagrammatic representation of the system, there is'shown a source of power comprising a line 25 connected by transformer 26 to the apparatus. A switch 27 connects the wires 15 and 16 to terminals 17 and 18 of one or the other of two vessels of the form described above. A suitable fluid circulating pump 28 is adapted to cause the flow of fluid from one vessel to the other continuously by means of pipe 29 and thereturn pipe 30. This circuiting system may be connected to an ordinary water main. The pipe connection 7 of each vessel is connected to a pipe line 31, which leads to a battery of pumps 32 and 33, which are driven by an electric motor 34 connected to the line 25 by means of switch 35. Pipe line 31 has therein suitable valves 41, 42, 43 and 44.- for a purpose to be hereinafter described.

In Fig. 3 is shown a vacuum tube comprising an evacuated envelope 36, an electrode stem 37 and three electrodes, a filament 38, a grid 39 and a plate or anode 40. The plate or anode 40 in this particular instance is the metal which is treated in accordance with this invention, although any other metal might be similarly treated within the spirit of the invention.

To operate the device, the switches 27 and 35 are closed. v The terminals 17 and 18 of one of the vessels 1 are then connected to the circuit Wires 15 and 16. We will assume for convenience that we desire to operate the left-hand vessel shown in Fig. 2. In this case the fluid pump 28 and the motor 34 having been started, the valves 41 and 44 are closed and the valve 42 is opened so that the interior of the vessel 1 is connected to the vacuum pump pipe line 31. At the same time the current through the strip 12 heats it, preferably, to incandescence. This glowing and evacuation is allowed to proceed for about five minutes during which time another strip 12 has been placed in the right-hand vessel 1 ready to be, in itsturn, treated. At the end of five minutes the wires 15 and 16 are transferred to the terminals 17 and 18 of the right-hand vessel 1. The valves 42 and 43 are closed and the valves 41and 44 are opened. This manipulation of the valves permits air to enter the lefthand vessel and connects the right-hand vessel to the right-hand pump system. The ribbon is then removed from the left-hand vessel and a new one placed therein while the lowing and evacuation is being carried onn' the right-hand vessel.

The strips of nickel thus treated for later use in audions and vacuum tubes are preferably 3 ft. long. It is a well-known step in the manufacture of vacuum tubes to evacuate the bulb 36 (Fig. 3) after the parts have been assembled in their ultimate positions and sealed into the bulb.

- which comprises a preliminary treatment of This invention,

the electrode material, greatly reduces the time required to completely denude the bulb and the electrode surfaces of occluded gases and other matter, and thereby achieves considerable economy in the manufacture of the tube. \Vhen the various parts of the tube have been assembled and sealed into the bulb, the tube is subjected to a main evacuation for about three quarters of an hour during which time the electrodes are glowed by current passing therethrough. The main evacuation is shortened by reason of the fact that the electrode material has been preliminarily glowed in the manner above described.

What is claimed is:

1. The method of manufacture of vacuum tubes which comprises subjecting a strip of electrode material to a vacuum, incandescing said strip while subjected to the vacuum,

forming electrodes from said strip, incorporating said electrodes into an electrode structure, assembling said electrode structure within a tube, exhausting said tube and heating said electrodes to incandescence during the evacuation of the tube. 2. The method of manufacture of vacuum tubes which comprises subjecting a strip of electrode material to a vacuum while heating said strip sufiiciently to drive off its oceluded gases, forming electrodes from said strip, incorporating said electrodes into an electrode structure, assembling said electrode structure Within a tube and exhausting said tube while heating said electrodes to the operating temperature of the tube.

In witness whereof, I hereunto subscribe my name this 17th dayof July A. D., 1919.

RUSSELL F. TRIMBLEJ. 

